Inverter needed or not

[Deleted User]

I'm new to this so I have the option of installing a 1000W or 2000W inverter in my T@B 320 year 2020.  Or the dealer said I can just buy a portable inverter that plugs in.  It plugs into the cigarette lighter 12v in the camper.  I'm going to be using my laptop constantly in the RV, charging camera batteries, iPad, Kindle that sort of thing.  Do I get the inverter installed (if so - which one) or use the plug in device?  It's not so much a money issue as it is convenience. (Edited as I found the "cigarette lighter" in the camper. )

pthomas745

I run my laptop with a 300 watt inverter either that I attach to a small battery I carry (35AH) or with a 12V laptop power adapter that plugs into the 12V ports in the trailer.  For a laptop, your dealer is correct.  You would only need a 1000/2000 watt inverter for items with a large power draw.

Your laptop draws amps depending on the size of the screen, and it isn't "too" much.  These are the results of a test I did just a few weeks ago:

"As near as my math will take me, my laptop, charged, running Lightroom and a You Tube video, is using about 2.5 amp hours or so on 12v.  (Check my math:  30 watts divided by 12 volts=2.5 amp hours)?

But if I want to charge the laptop and run those items, the amp hour usage would be about 5 amp hours.  (Not to mention the percentage loss from the inverter inside the trailer)."

Not sure what your battery setup is, but even on my "stock" battery with 35AH available I can run my laptop a long time.

Here is the entire thread on using a laptop. There are several different options for laptop power.

https://tab-rv.vanillacommunity.com/discussion/comment/118057#Comment_118057

DigitalSorceress

If you plan to use your laptop often, see if you can get a 12v direct adapter for it.. Amazon sells a lot of them but MAKE SURE YOU GET THE RIGHT ONE... it's easy to accidentally order the wrong one.. been there, done that.

Anyway, if there is a direct from 12v adapter for your model laptop available it will over all work better/use less battery than using an inverter.

Trailpixie

The 1,000 or 2,000 watt inverters are overkill for what you describe. The application I have most often seen that demands high-end inverters is CPAP and power tools like circular saws. Otherwise a 300 or 600 watt standalone inverter will be fine for all those things. All of your devices use DC power, and many of them have adapters for pre-installed USB or cig lighter plugs that you can use instead of the inverter. That laptop is the only thing that will come close to stressing a 300 watt inverter, and it still has plenty of power. 

For me, the only reason for you to get one installed is for the convenience of a permanently mounted 110 VAC plug. Some people don't like having it permanently installed because it is one more thing that can go wrong and be difficult to replace. Inverters can be a bit unreliable, so having them standalone may be a good idea. I have had good luck setting the inverter on the shelf behind the couch back and plugging it in back there. I then run the 110v cord over the seatback and to my laptop. I also recently upgraded my Television so that I have this.

pthomas745

@DigitalSorceress , that makes me think:  would the difference between the direct 12v adapter and plugging in through an inverter save just the inverter's "efficiency?"  So, if an inverter costs me 15 percent, is that 15 percent the power savings using the 12v adapter?  Or would it be more?

DigitalSorceress

@pthomas745  I'm not sure but from a theoretical perspective, a well made switching power supply can be 98% efficient...   if your inverter is losing 15% you'd likely do better with the 12v laptop adapter. they usually only cost like $30..

I bought one for my work laptop but accidentaly ordered the wrong one and had to send it back.. have not yet gotten around to ordering the right one otherwise I'd do a bit of a test..  compare inverter powering laptop draw to direct 12v laptop draw

davel4wa

Power inverters are never 100% efficient. Without actually measuring the current being sourced from the battery it would be hard to know if an inverter powering your device using AC power or a 12V adapter is most efficient. Depending on your laptop the voltage provided by your factory power adapter could be higher than 12V. The label on your factory power adapter will tell you what the output voltage is. Here is where the efficiency argument goes a little sideways. IF the voltage required by your laptop is greater than the 12V available in your trailer then how do we get the higher voltage required by your laptop? A 12V adapter, in order to achieve an output voltage higher than the 12V input voltage uses a circuit called a DC to DC converter. What happens here is the DC input voltage is converted to an AC voltage and then converted back to DC at the desired voltage level. So you see we have another conversion process that will not be 100% efficient. The difference in efficiency of the inverter and the 12V adapter is unknown without actually measuring the battery current required. One way to get an idea of efficiency, while not scientific for sure, is to lay your hand on the conversion device and see how warm it is. Heat produced during conversion is power lost, unless you are using it to warm your trailer 😊.
One other thing to consider is that some things you may want to use can only run on AC, like a hair dryer, a microwave (if you have one). A lot of things you use at home on AC power have special 12V versions for travel use. You can duplicate all of those things to use only in your trailer or your vehicle, certainly but do you want to? Most of those 12V versions come at a higher price than the AC versions you already own.

dCliffhanger

One needs to keep in mind that if you get a 2000 watt inverter and should you be tempted, or mistakenly, plug in a 1500 watt item such as a hair dryer, it will drain a 100 Amp hour battery to 50% in under 24 minutes.

I installed a 600 watt sine wave inverter and that's probably more that any single battery will support for very long. It takes 110 volts or a generator to supply that kind of sustained power.

dCliffhanger

A followup, a cigarette lighter is not wired, or fused, to take 1 or 2000 watts.  That's 166 amps at 12 volts.

pthomas745

But, it would only take 2 minutes to dry my hair.

jkjenn

I have been known to plug my hairdryer I to my GZ Yeti 1000 Lithium.